The present invention relates to a process for making methyl fluoride by the reaction of methanol and aqueous HF.
In the past, the fluorination of organic compounds by reaction with hydrogen fluoride has ordinarily been carried out under anhydrous conditions. Even under anhydrous conditions, many such attempted reactions have been found to be impractical or to be essentially inoperative. The preparation of alkyl fluorides by the reaction of primary alcohols with hydrogen fluoride in particular has been considered impossible in any practical sense although an old reference describes a partially successful pressure reaction of anhydrous HF with lower alcohols, see Meslans, Compte rend. 115, 1080 (1892). However, the water of reaction formed in the process caused the reaction to be reversible. Tertiary alkanols are known to react with aqueous hydrofluoric acid to produce the corresponding fluorides, see Cooper et al., J. Chem. Soc. 1937, 1185.